The invention relates to a rear axle for motor vehicles, with an axle beam of rigid design, running at right angles to the lengthwise axis of the vehicle, said axle beam being mounted pivotably to the vehicle body by a support bearing located on the central lengthwise axis of the vehicle and by guide bearings, through two trailing arms connected to the axle beam, said axle beam further being held away from the vehicle body by shock absorber struts.
German Offenlegungsschrift No. 1,911,795 teaches a rear axle for motor vehicles, said axle comprising a rigid, bent crosstube as well as trailing arms which are torsion- and bending-resistant, said trailing arms being pivotably mounted in bearings on the crosstube and the vehicle body. The rear axle is mounted to the vehicle body by three bearings, whereby, in addition to the two outer bearings on the crosstube, a third guide bearing is provided in the middle of the crosstube, said third bearing occupying a position on the central lengthwise axis of the vehicle and extending in the horizontal lengthwise direction of the vehicle. This central guide bearing serves primarily to accept lateral and longitudinal forces. A rear axle of this design is expensive to construct and requires the use of bearings for the trailing arms which must be adjusted precisely, especially at the points where the trailing arms are attached to the crosstube. Forces are transmitted to the body primarily via the central guide bearing when a rear axle of this type is used, whereby only a small support base is provided for the rear axle. Moreover, it is also disadvantageous that the rigid arms prevent the axle from producing a stabilizing effect when the vehicle rounds a curve.
Another object of the invention is to provide a rear axle of the type described hereinabove, said axle having a support base which meets the corresponding requirements and makes it possible simultaneously to produce a stabilizing effect when the vehicle traverses a curve.
This object is achieved by the features of preferred embodiments of the invention which include the fact that an axle beam is connected with two trailing arms to form a one-piece wheel guiding element having an instantaneous rotational pole located rearwardly of the rotational axis of the vehicle rear wheels.
The advantages achieved with the invention include the fact that the simple design of such a rear axle permits preassembly of the complete axle unit without costly adjustments being necessary after installation. Only three articulation points to the vehicle body are provided with this rear axle, whereby a relatively large support base is produced and a satisfactory transmission of force to the vehicle body is achieved. The elasticity of the guide bearings for the trailing arms permit a high degree of ride comfort by lengthwise and transverse springing, without having a negative effect on handling. Moreover, it makes possible wheel guidance with changes in the kingpin angle and in the toe-in, as well as keeping the wheel gauge constant, as with a rigid axle. In addition, there are no undesirable elastic changes in toe-in when traveling in a straight line under varying load conditions. On the other hand, when rounding a curve, desirable positive understeer in response to lateral forces is achieved.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.